Enhanced Piezoelectric Shunt Design

Abstract

Piezo ceramic patches connected to electronic shunt circuits have formed successful vibration reduction devices. Here a new shunt circuit design with additional capacitors is presented. One drawback of existing electronic shunt circuits is the large inductance required when suppressing low frequency vibration. Also, the large internal resistance associated with this high inductance value exceeds the optimal design resistance needed for vibration suppression. To solve these problems, a modified and improved piezoelectric shunt circuit is designed by connecting additional capacitors in parallel. This design is experimentally demonstrated for a desired tuned mode of an aluminum beam. The results indicate that improved electronic passive damping can significantly reduce the structural vibration response with half of the inductance previously required.

A critical analysis of electric shunt circuits employed in piezoelectric passive vibration damping

“…Moreover, it is proved that the exponential time decay rate of vibrations attained by using the RL-C parallel shunt circuit is 1/ √ 1 + α times the one relevant to the RL series circuit. This fact was not observed in [14] and limits the value of the external capacity C in the shunt circuit and, consequently, the amount of reduction of the tuning inductance L.…”

“…Adopting the approach used for the analysis of the RL series circuit, the shunt circuit proposed in [14], schematically represented in figure 3, is now considered. The following expressions hold:…”

“…This problem can be partially overcome by using a synthetic inductor [13], able to furnish very high values of inductance but also presenting high values of resistance, which can become greater than the optimal value of resistance needed by the passive control law. To this end Park and co-workers [14] proposed an enhanced shunt circuit, consisting of a capacitor C and a RL branch in parallel (RL-C parallel circuit); the parallel capacitor C allows the reduction of the optimal value of the inductance L by a factor 1 + α, where α is the ratio between the external capacity C and the capacity C p of the piezoelectric actuator.…”

“…Several criteria have been adopted in the literature in order to optimally choose the electrical parameters of a shunt circuit. A simple technique is based on transfer function considerations [6,15] (transfer function optimization method) and applies only in the case of negligible mechanical damping; it was employed in [11,12,14] for the optimization of the shunt circuits cited above in the approximation of vanishing mechanical damping.…”

Vibration Mitigation of Bladed Structures Using Piezoelectric Digital Vibration Absorbers

“…These branches are tuned to resonate at the targeted resonance frequency of the mechanical structure. In order to realize high inductance values that are usually needed in these types of applications, synthetic inductors are commonly used [2]. Alternatively, a full digitalization of the desired electrical shunt circuit can be realized with so-called digital vibration absorbers (DVA).…”